/* * Copyright (c) 2014, Fuzhou Rockchip Electronics Co., Ltd * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #include #include #include #include #include #include #include #include "dw_mmc.h" #include "dw_mmc-pltfm.h" #define RK3288_CLKGEN_DIV 2 struct dw_mci_rockchip_priv_data { struct clk *drv_clk; struct clk *sample_clk; int default_sample_phase; }; static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios) { struct dw_mci_rockchip_priv_data *priv = host->priv; int ret; unsigned int cclkin; u32 bus_hz; if (ios->clock == 0) return; /* * cclkin: source clock of mmc controller * bus_hz: card interface clock generated by CLKGEN * bus_hz = cclkin / RK3288_CLKGEN_DIV * ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div)) * * Note: div can only be 0 or 1 * if DDR50 8bit mode(only emmc work in 8bit mode), * div must be set 1 */ if (ios->bus_width == MMC_BUS_WIDTH_8 && ios->timing == MMC_TIMING_MMC_DDR52) cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV; else cclkin = ios->clock * RK3288_CLKGEN_DIV; ret = clk_set_rate(host->ciu_clk, cclkin); if (ret) dev_warn(host->dev, "failed to set rate %uHz\n", ios->clock); bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV; if (bus_hz != host->bus_hz) { host->bus_hz = bus_hz; /* force dw_mci_setup_bus() */ host->current_speed = 0; } /* Make sure we use phases which we can enumerate with */ if (!IS_ERR(priv->sample_clk)) clk_set_phase(priv->sample_clk, priv->default_sample_phase); /* * Set the drive phase offset based on speed mode to achieve hold times. * * NOTE: this is _not_ a value that is dynamically tuned and is also * _not_ a value that will vary from board to board. It is a value * that could vary between different SoC models if they had massively * different output clock delays inside their dw_mmc IP block (delay_o), * but since it's OK to overshoot a little we don't need to do complex * calculations and can pick values that will just work for everyone. * * When picking values we'll stick with picking 0/90/180/270 since * those can be made very accurately on all known Rockchip SoCs. * * Note that these values match values from the DesignWare Databook * tables for the most part except for SDR12 and "ID mode". For those * two modes the databook calculations assume a clock in of 50MHz. As * seen above, we always use a clock in rate that is exactly the * card's input clock (times RK3288_CLKGEN_DIV, but that gets divided * back out before the controller sees it). * * From measurement of a single device, it appears that delay_o is * about .5 ns. Since we try to leave a bit of margin, it's expected * that numbers here will be fine even with much larger delay_o * (the 1.4 ns assumed by the DesignWare Databook would result in the * same results, for instance). */ if (!IS_ERR(priv->drv_clk)) { int phase; /* * In almost all cases a 90 degree phase offset will provide * sufficient hold times across all valid input clock rates * assuming delay_o is not absurd for a given SoC. We'll use * that as a default. */ phase = 90; switch (ios->timing) { case MMC_TIMING_MMC_DDR52: /* * Since clock in rate with MMC_DDR52 is doubled when * bus width is 8 we need to double the phase offset * to get the same timings. */ if (ios->bus_width == MMC_BUS_WIDTH_8) phase = 180; break; case MMC_TIMING_UHS_SDR104: case MMC_TIMING_MMC_HS200: /* * In the case of 150 MHz clock (typical max for * Rockchip SoCs), 90 degree offset will add a delay * of 1.67 ns. That will meet min hold time of .8 ns * as long as clock output delay is < .87 ns. On * SoCs measured this seems to be OK, but it doesn't * hurt to give margin here, so we use 180. */ phase = 180; break; } clk_set_phase(priv->drv_clk, phase); } } #define NUM_PHASES 360 #define TUNING_ITERATION_TO_PHASE(i) (DIV_ROUND_UP((i) * 360, NUM_PHASES)) static int dw_mci_rk3288_execute_tuning(struct dw_mci_slot *slot, u32 opcode) { struct dw_mci *host = slot->host; struct dw_mci_rockchip_priv_data *priv = host->priv; struct mmc_host *mmc = slot->mmc; int ret = 0; int i; bool v, prev_v = 0, first_v; struct range_t { int start; int end; /* inclusive */ }; struct range_t *ranges; unsigned int range_count = 0; int longest_range_len = -1; int longest_range = -1; int middle_phase; if (IS_ERR(priv->sample_clk)) { dev_err(host->dev, "Tuning clock (sample_clk) not defined.\n"); return -EIO; } ranges = kmalloc_array(NUM_PHASES / 2 + 1, sizeof(*ranges), GFP_KERNEL); if (!ranges) return -ENOMEM; /* Try each phase and extract good ranges */ for (i = 0; i < NUM_PHASES; ) { clk_set_phase(priv->sample_clk, TUNING_ITERATION_TO_PHASE(i)); v = !mmc_send_tuning(mmc, opcode, NULL); if (i == 0) first_v = v; if ((!prev_v) && v) { range_count++; ranges[range_count-1].start = i; } if (v) { ranges[range_count-1].end = i; i++; } else if (i == NUM_PHASES - 1) { /* No extra skipping rules if we're at the end */ i++; } else { /* * No need to check too close to an invalid * one since testing bad phases is slow. Skip * 20 degrees. */ i += DIV_ROUND_UP(20 * NUM_PHASES, 360); /* Always test the last one */ if (i >= NUM_PHASES) i = NUM_PHASES - 1; } prev_v = v; } if (range_count == 0) { dev_warn(host->dev, "All phases bad!"); ret = -EIO; goto free; } /* wrap around case, merge the end points */ if ((range_count > 1) && first_v && v) { ranges[0].start = ranges[range_count-1].start; range_count--; } if (ranges[0].start == 0 && ranges[0].end == NUM_PHASES - 1) { clk_set_phase(priv->sample_clk, priv->default_sample_phase); dev_info(host->dev, "All phases work, using default phase %d.", priv->default_sample_phase); goto free; } /* Find the longest range */ for (i = 0; i < range_count; i++) { int len = (ranges[i].end - ranges[i].start + 1); if (len < 0) len += NUM_PHASES; if (longest_range_len < len) { longest_range_len = len; longest_range = i; } dev_dbg(host->dev, "Good phase range %d-%d (%d len)\n", TUNING_ITERATION_TO_PHASE(ranges[i].start), TUNING_ITERATION_TO_PHASE(ranges[i].end), len ); } dev_dbg(host->dev, "Best phase range %d-%d (%d len)\n", TUNING_ITERATION_TO_PHASE(ranges[longest_range].start), TUNING_ITERATION_TO_PHASE(ranges[longest_range].end), longest_range_len ); middle_phase = ranges[longest_range].start + longest_range_len / 2; middle_phase %= NUM_PHASES; dev_info(host->dev, "Successfully tuned phase to %d\n", TUNING_ITERATION_TO_PHASE(middle_phase)); clk_set_phase(priv->sample_clk, TUNING_ITERATION_TO_PHASE(middle_phase)); free: kfree(ranges); return ret; } static int dw_mci_rk3288_parse_dt(struct dw_mci *host) { struct device_node *np = host->dev->of_node; struct dw_mci_rockchip_priv_data *priv; priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; if (of_property_read_u32(np, "rockchip,default-sample-phase", &priv->default_sample_phase)) priv->default_sample_phase = 0; priv->drv_clk = devm_clk_get(host->dev, "ciu-drive"); if (IS_ERR(priv->drv_clk)) dev_dbg(host->dev, "ciu_drv not available\n"); priv->sample_clk = devm_clk_get(host->dev, "ciu-sample"); if (IS_ERR(priv->sample_clk)) dev_dbg(host->dev, "ciu_sample not available\n"); host->priv = priv; return 0; } static int dw_mci_rockchip_init(struct dw_mci *host) { /* It is slot 8 on Rockchip SoCs */ host->sdio_id0 = 8; if (of_device_is_compatible(host->dev->of_node, "rockchip,rk3288-dw-mshc")) host->bus_hz /= RK3288_CLKGEN_DIV; return 0; } /* Common capabilities of RK3288 SoC */ static unsigned long dw_mci_rk3288_dwmmc_caps[4] = { MMC_CAP_CMD23, MMC_CAP_CMD23, MMC_CAP_CMD23, MMC_CAP_CMD23, }; static const struct dw_mci_drv_data rk2928_drv_data = { .init = dw_mci_rockchip_init, }; static const struct dw_mci_drv_data rk3288_drv_data = { .caps = dw_mci_rk3288_dwmmc_caps, .set_ios = dw_mci_rk3288_set_ios, .execute_tuning = dw_mci_rk3288_execute_tuning, .parse_dt = dw_mci_rk3288_parse_dt, .init = dw_mci_rockchip_init, }; static const struct of_device_id dw_mci_rockchip_match[] = { { .compatible = "rockchip,rk2928-dw-mshc", .data = &rk2928_drv_data }, { .compatible = "rockchip,rk3288-dw-mshc", .data = &rk3288_drv_data }, {}, }; MODULE_DEVICE_TABLE(of, dw_mci_rockchip_match); static int dw_mci_rockchip_probe(struct platform_device *pdev) { const struct dw_mci_drv_data *drv_data; const struct of_device_id *match; if (!pdev->dev.of_node) return -ENODEV; match = of_match_node(dw_mci_rockchip_match, pdev->dev.of_node); drv_data = match->data; return dw_mci_pltfm_register(pdev, drv_data); } static struct platform_driver dw_mci_rockchip_pltfm_driver = { .probe = dw_mci_rockchip_probe, .remove = dw_mci_pltfm_remove, .driver = { .name = "dwmmc_rockchip", .of_match_table = dw_mci_rockchip_match, .pm = &dw_mci_pltfm_pmops, }, }; module_platform_driver(dw_mci_rockchip_pltfm_driver); MODULE_AUTHOR("Addy Ke "); MODULE_DESCRIPTION("Rockchip Specific DW-MSHC Driver Extension"); MODULE_ALIAS("platform:dwmmc_rockchip"); MODULE_LICENSE("GPL v2");